In U.S. application Ser. No. 411,112, filed Oct. 30, 1973, a device is presented which aids in automobile parking instruction which consists of two portable and resiliently suspended curb elements employed in combination with a plurality of pressure sensitive elements supported on the parking surface in front of the curbs, so as to signal the distance away from the curbs of the parked student vehicle tires with respect to the curbs.
A pair of portable base elements are provided for resilient suspension of corresponding curb elements above the parking surface. The curb elements may be, for example, 10 to 20 feet in length and aligned with respect to each other, so as to define a conventional or otherwise adjustable parking surface. Pneumatic signaling means in a continuous circuit are laid out upon the parking surface in front of the curb elements and between the base elements and the curb elements. As a result, the student driver in attempted parking depresses that part of the pneumatic signaling means laid out upon the parking surface in front of the curb elements. The depression of the vehicle tires upon the pneumatic signaling means activates the signaling and scoring means resulting in a scoring of the parking effort and visual or audible signaling of the distance away from the curbs of the front and rear tires of the parked student vehicle.
A pressure sensitive signaling means may include pneumatic lines or alternatively other pressure sensitive means which may be monitored electrically. The pneumatic lines, incorporating the apertured diaphragm end valve can be constructed in a continuous circuit, such that the air pressure inside the semiclosed system can adjust to the pressure outside the system when the system is not in use and such that the air pressure does not leak from the circuit upon depression by the vehicle tires when the system is in use and such that upon release of the weight of the vehicle tires the system is permitted to take in outside air so as to equalize the inside pressure with the air pressure outside the system, thus readying the system for the next user.